The present invention relates to an oil pan, in particular for an internal combustion engine, having a drain mechanism comprising a valve body which is inserted into a drain opening in an oil pan wall and which is adjustable between closed and open positions.
Oil pans of this type, which are arranged on the underside of an internal combustion engine, must be designed to be stable to withstand high forces, and also to withstand high mechanical forces to which they may be subjected, for example, from a stone strike or from the vehicle scraping the ground. There are also known embodiments of oil pans made of metal or even a one-piece injection-molded part made of polyamide or polypropylene, as described in published European patent application no. EP 1,041,253. To be able to drain the oil out of the oil pan, a drain opening is provided in the bottom of the pan which can be closed by an adjustable closing element. In the case of oil pans made of metal, this closing element may be designed as an oil drain screw which is screwed into the drain opening under pressure via a copper gasket, so that a leak-proof condition is established. In the case of oil pans made of synthetic resin material, the required imperviousness can hardly be established merely by a screw connection of the oil drain plug to the wall of the oil pan because only a limited introduction of force is possible for strength reasons, but this is not sufficient to achieve reliable fluid-tightness. Instead, threaded inserts which are inserted into the opening to be sealed may be used. However, such measures are associated with a relatively great complexity and cost. Furthermore, there is the risk of the threaded insert being ripped out if it is subjected to a force which is too high.